Pig-bed-molding machine



Sept. 8. 1925. 1,552,582

s. STEWART PIG BED MOLDING MACHINE Filed Feb. 1923 9 Sheets-Sheet 1Jnvmlm Samuel 511W.

Sept. 8, 1925.

S. STEWART PIG BED MOLDING MACHINE Filed Feb. 5,

9 Sheets-Sheet 2 S. STEWART PIG BED MOLDING MACHINE Sept. 8, 1925.1,552,582

Filed Feb. 5, 1923 9 Sheets-Sheet 3 lwcuim.

SHMUEL STEW PZ Sept. 8, 1925.

s. S f TEWART PIG BEDQMOLDING MACHINE Filed Feb. s. 1923 9 Sheets-Sheet4 "TIT l'l TTI Sept. 8, 1925.

9 ts-Skgeet Filed Feb. 5. 1923 STEWART Sept; 8, 1925.

S. STEWART PlG BED MOLDING MACHINE Filed Feb. 5, 1925 9 Sheets-Sheet 6STEWART Sept. 8. 1925.

S. STEWART PIG BED MOLDING MACHINE Filed Feb. 5, 1923 9 Sheets-Sheet 7Sept. 8, 1925. 1,552,582

S. STEWART PIG BED MOLDING MACHINE Filed Feb. 5. 1923 9 Sheets-Sheet, 8

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S. STEWART PIG BED MOLDING MACHINE Filed Feb. 5, 1925 9 Sheets-Sheet 9SQMUEL S EWQR Patented Sept. 8, 1925.

UNITED STATES PATENT OFFICE.

SAMUEL STEWART, or BIRMINGHAM, ALAB M ASSIGNOR or ONE-HALF To 'JAMEs M.oosrnn, or GADSDEN, ALABAMA.

PIG-BED-MOLDIN G MACHINE.

Application filed February 5, 1923. Serial No. 616,919.

T 0 aZZ whOm it may concern:

Be it known that I, SAMUEL STEWART, a citizen of the United States ofAmerica, residing at Birmingham, in the county of Jefierson and State ofAlabama have in vented certain new and useful Improvements inPig-Bed-Molding Machines, of which the following is a specification.

My invention relates to a pig bed molding machine which is adapted toperform mechanically all of the work required to prepare and form themolds bed for pig iron.

My invention contemplates, in its preferred embodiment, the combinationin a traveling machine of all of the various instrumentalities requiredfor preparing the sand bed in the best possible manner in ad- Vance ofthe mold roller so that the latter can most effectively perform itswork, and to this end the mechanism comprises novel and effective meanswhich in respective order will first plow the sand bed and remove pigsor pieces of iron left in the bed from the previous run; next willscreen the sand and deposit it back in the bed, this operationpreferably comprising the use of elevating bucket which raisepractically all of the sand used in making the molds and pass it backthrough a screen which collects and removes from the sand foreign matternot caught by the scrap plows; next, using means such as a magneticscrap collector to remove metallic particles which pass the screen; nextgrading the screened sand bed and adding such additional sand as may,from time to time be required to maintain the desired grade of the sandbed; next by means of a series of plows, one immediately in advance ofand aligning with the runner mold and each pig mold, opening up the bedso as to eliminate as far as possible duty on the mold roller; and nextutilizing a mold roller and designing it to form in the plow tracks thepig molds which lie level as formed in the sand bed.

My invention moreover contemplates the provision of means for theadjustment of the various mechanisms to the end that they may be set intheir different operating positions or raised to inoperative positionwhen the machine is not in operation.

A further distinctive feature of my invention is gearing the machine oneach side to racks which hold its transverse axis at right angles alwaysto its line of travel, and in so co -relating the drive to the rackgears and the mold wheel that they shall have similar peripheral speeds.

A further distinctive feature is the formation of the runner mold wheelin sections at right angles to its axis and the mounting of saidsections for rotation independently of each other and of the moldroller, so as to avoid any objectionable dragging of this mold wheelthrough the sand.

A further feature of my invention relates to mounting, in a selfcontained ma chine of the character described, a water tank withconveniently arranged sprays for moistening the sand to the desiredextent and at the desired points relative to the several sand treatingmechanisms.

A further distinctive feature is the pro vision of cam means, controlledby the pig mold roller and adapted automatically to raise and lower thesand plows in advance of said roller so as to reduce the depth of theircut at the points where the recessed patterns forming the wall behindeach sow would strike, thus causing both the sow and pig patterns toperform substantially equal duty tho-ugh penetrating to different depthsbelow the initial grade of the sand bed.

A further distinctive feature is to so modify the curvature, intransverse cross section, of the pig mold roller as to cause the printsformed by the pig molds or patterns to lie ho izontally in steppedlevels which are disposed crosswise of a bed which bed must necessarilypitch sufficiently in a lengthwise direction to cause the metal tofollow down the runner.

My invent-ion also contemplates the effective provision of means forcontrolling the raising and lowering of the various sand treatingappliances from an operators platform and of incorporating in the drivefor the machine means for enabling it to be returned at relatively fastspeed after forming a pig bed.

My invention also particularly contemplates means for facilitating theangular adjustment of the sand treating and molding mechanism toaccommodate it to pig beds having various lateral pitches, saidadjustment being accomplished at be ame time for all parts by raising orlowering either side of their supporting frame relatively to itssupporting track wheels, and thus avoiding the necessity for adjustingthe various parts separately. 3

My invention also comprises the novel details of construction andarrangements of parts which are hereinafter more particularly describedin the accompanying speci fication, and which are pointed out intheappended claims, reference being had to the accompanying drawings, whichform a part of this specification, and which seek to illustrate onlyw-hatl regardas the i preferred vi embodiment of my invention.

In the drawings V Fig. 1 is av plan view oft-he machine.

Fig. 2 is a side elevation of Fig. 1 with the rack pinions bro-ken away.7

Fig. 3 is a detail view-showing the rack and pinion drive omitted from-Fig. 2.

Fig. 4 is a rear end elevation of the drive to the pinions.

Fig. 5 is a cross-sectional View taken on the line 55 of Fig. 2 showingthe main mold roller and the drive for adjusting it.

Fig. 6 is a sectional View taken on the line 66 of Fig. 2' showing inrear elevation the plows preceding the mold roller.

Fig. 7 is a-sectional view taken on the line 7-7 of Fig. 2 and showingin rear elevation the shaking screens and theirdrive-together with theoperators platform and control elements.

Fig. 8 is a cross-sectional view on the line 88 of Fig. 2 showing-inrear elevation the sand elevator. 7

Figs. 9, 10 and 11 are enlarged side views of portions of the machine,the'three-views respectively showing the rear end, the intermediatesection and the forward end of the machine.

Fig. 12 is an enlargedcross-sectional view through the mold roller.

Fig. 13 is an enlarged-view of the-mold .rollershowing the runner moldand acrosssectional view through the pig bed.

Fig. 14: is a longitudinal cross-sectional view of the molded pig bed.

Fig. 15 is a detail cross-sectional view of the sand bin and its sanddischarge valve.

Figs. 16,17, 18 and 19 are respectively cross-sections, elevations andplan of the mold and bucket wheel. elevator and the frame tiltingmechanism.

Similar reference numerals referto similar parts throughout thedrawings.

The machine, as illustrated in its pre ferred embodiment, comprises arigid marginal frame, preferably fabricated of structural iron or steelsuitably braced to have the necessary rigidity and strength to sup Iport the operating mechanism as it travels back andforth o'ver thepigbed on the wheels 2 which at the rear are mounted on a shaft 3 and atthe front on a shaft 4, and which travel on tracks 5 suitably mounted oneach side of the pig'bed. On the overhung ends of the shaft 3 I mountpinions 6 which mesh with racks 7 disposed parallel with and adjacent totracks 5. The shaft 3'is suit-ably supported in bearings 8 underhungfrom the sides of the frame and 'the'pitch'line of the pinions is equalto the diameter of the-wheels 2 so that as the ma- 16, under the controlof a clutch'18, can be adapted to move the machine in a forwarddirection by means of a sprocket 19 looseon I shaft 16, chain 20 andsprocket 21 fast on the shaft 3, or by reversing the'm'otor 9 to movethemachine in a reverse direction and at a much higher rate of speed bymeans of a sprocket 22 loose on shaft16, chain 23' and sprocket 24 alsofast on shaft 3. By this means the machine can be driven forward slowlywhile forming the mold bed and can be returned quickly after completingits work. 7 M j The shaft 3 carries at each end'a sprocket 25, each ofwhich is connected by a chain 26 to a sprocket 27 on the mold rollershaft 28. This shaft 28 is mounted in journal boxes 29 which arefreetoslide vertically in gui des 30, each being controlled in itsadjustments by means of a pair of links 31, which links straddle theside I-beam of the framephaving eyes at their lower ends to receive hubextensions 29 on the boxes 29 in which the shaft 28 turns, and beinghung from a cross head 32 which is vertically adjustable in a stanchion33 by a screw 34, which atitsupper end is in threaded engagement with abeveled gear 35, which is held against raising or lowering by thestanchion. :These gears 351nesh with pinions 36 which are mounted oncross shafts 37, which shafts at their inner ends are provided withgears 38 which mesh gears 39 at each end 'of the shaft of an electricmotor 40. The threads on the screws 34 are a reverse pitch to cause themto raise -or lower the boxes simultaneously. This makes provision forthe vertical adjustment of the mold roller to set it to the desiredworking level or to raise it out of operating position. To control thepitch of the roller endwise or from side to side of the pig bed, thewheelv shaft 3 at one side is shown mounted in a journal box 41 which isfree to slide vertically in the guides 42 forming part of the bearing 8,the vertical adjustments of the frame 1 relative to the box 41 beingcontrolled by a pair of links 43 which engage the hub extensions 41 onthe box 41 and straddle the side of the frame 1, being at their upperends hung from a cross head 44 on a screw 45 on which a worm wheel 46 isthreaded. This worm wheel 46 is adapted to mesh a worm 47 operated by ahand wheel 48 on the worm shaft which turns in suitable bearings 49 onthe stanchion 50 for the cross head. The worm wheel is held in positionbetween the upper and lower bearings 51 in the stanchion 50. A similaradjusting rigging for the frame 1 relative to the journal box 41 forshaft 4 on the same side of the machine at the front is provided, sothat by manipulating these worm gearings the side of the frame can beraised and lowered with all the mechanism carried thereby to give thedesired lateral pitch to the machine as a whole and hence to the moldroller. Obviously such an arrangement may be provided for the axle boxes41 on either side or both sides of the machine as desired.

A mold roller 52, the detail construction of which will be laterdescribed, is mounted fast on the shaft 28, and at both ends adjacent tothe mold roller driving gears 27 l mountcams 53. These cams aresymmetrical and have four high points spaced 9r apart and the moldroller is provided about its circumference with four axial series of pigmold patterns 54, each of which axial series of such patterns isco-ordinated with one of the high points of the cams 53. The cams engageand operate bell cranks mounted in suitable bearings 56 on the frame andeach connected at its free forward end by a swinging link 57 with an eye58 fast to a cross member 59 mounted for vertical play in underhungguides or stanchions 60. The cross member 59 constitutes plow carrierand has connected along its bottom edge in any suitable manner, a seriesof plows 61, one of which is disposed in alignment with eachcircumferential row of pig mold patterns 54 on the mold roller. Theplows are so placed relatively to, and the points of the cams are soco-related with, the mold roller that the plows as they are raised andlowered will vary the depth of their cut to roughly correspond to theirregular contour of the patterns on the mold roller that will come intoengagement therewith, so that the duty on the patterns, regardless oftheir height relative to a circle having the smallest diameter of themold roller, will be practical 1y uniform.

The mold roller carries at one end a runner mold wheel 62 and I mount inadvance of this a plow 63 pivotally connected to bearings 64 underhungfrom the frame. The plow is provided with an eye 65 to which anoperating rod 66 is pivotally connected, this rod at its upper end beingconnected to a bell crank lever 67 pivoted to the sand bin 68 andadapted to be operated by a rod 69 leading forward of the machine to theoperators platform 70, where by means of one of the levers 71 the plowcan be raised, lowered or set in any desired operating position. Therunner mold wheel 62 being of uniform diameter does not require thatthis plow 63 be raised or lowered except when it is desired to run themachine back over the bed.

Immediately in advance of the plows and extending the full width of themold roller is a sand bin 68 which has in its bottom a rotat-ing sandvalve 72 mounted on a shaft 74 journaled in suitable bearings 7 3 in theside walls of the bin. East on the outer ends of the valve shaft 74 is asprocket wheel 75' driven by a sprocket cham 76 from sprocket gear 77 ona counter-shaft 78 driven a by gearing 78- from an electric motor 79mounted on the frame at one side. The cross section of the sand valve isillustrated more clearly in Fig. 6, and it will feed only intermittentlyas it is rotated. Its motor is started and the valve is driven when itis necessary to supply additional sand to make up the loss of sand fromthe bed. The bin 68 therefore contains only a supplemental supply ofsand for replacement purposes. Along the bottom of the bin 68 I providean extension wall 80 forming a. chute for the sand and to the lower edgeof this chute I connect by hinges 81 a grading plate 82 which isreinforced by a transverse angle iron 83 and which can be raised andlowered by rods 84' connected below to eyes 85 on the grading plate andabove to bellcrank levers 86 mounted on a shaft 87, and each having itsfree arm connected by a rod 88 to one of the operating levers on theoperators platform. The shaft 87 is mounted to turn in a hollow shaft 87which is journaled in suitable bearings in the ends of the sand bin 68and the solid shaft 87 extends through the hollow shaft and has a. bellcrank 86 keyed to each overhung end thereof.

I mount on the shaft 87 near each end a bell crank lever 86 from each ofwhich depends a rod 89 which is preferably tubular so that electriccables 90 can pass through one or both of these to a magnet 91 hingedlyconnected to the lower end of the rods 89 and disposed to travel inclose proximity to the sand bed for the purpose of collecting smallpieces of metal left in the screened sand. The magnet is in the form ofa bar extending the full width of the bed and it can be raised andlowered as desired.

Immediately in advance of the magnet is a transversely disposed shakingscreen pref-- erab y composed of a lower screen having eccentric shaft99 which carriesit hree .eccen trics,two.of which are connected bystraps 100 to the links 93 which support-the screen 92 at one end, andthe'third eccentric, set at approximately 180 relative to the-firstmentioned eccentrics, is, connected by a strap 101 toone of the-links 97which support the upper screen 9.6. The eccentric shaft has fast thereona gear 10.3 driven byv a motor 104, which motor is continuously drivenduring the operation of the machine and causes the screens toreciprocate constantly in opposite directions. The screens will act tosift, break upand deliver sand to the bed inadvance of the grading plate85. The screen bottom 95 ispreferably formed in two longitudinal half.sections hinged to; the sides 92-andprovidcdwith latches 106, by meansof which they are held. closed. .By releasing .the latches. the .screenbottomsections will swing by gravity .to the. open position which isshown in dotted lines, Fig. 2, and will drop all. scrap. thereon.

Immediately in advance. of the screens is a. rotary sand elevator inthe-form of .a bucket wheel 107 which extends the full width of the moldroller, being mounted on a shaft;108..jour,naled in bearing-boxes 109vertically adjustable in housings ,110. The boxes are verticallyiadjustable sby a mechanism similar to. that described inconnection withthe vertical adj ustments; of the and has a drive at each end comprising a sprocket 114 fast to the wheel, a chain 115 and a sprocket 116fast on its respective shaft 117. These shafts 117 carry gears 1'18meshing gears; 119 at opposite ends of the shaft of. a motor 120. Thismotor is alsomounted. on the. platform 112 andis driven continuouslyduring. the operation of the machine and acts to rotate the bucket wheelcounter-clockwise, as viewed in Fig. 2. The wheel between the frame 1'is provided with longitudinal curved blades 121 which it, ,on thesandscreen.

the bed .in advance of the sand treating mechanism and will elevateitand deposit practicallyv all of the sand usedinforming the molds will betaken up, worked over and returned to the bed in advance of itstreatment by the plows and mold roller.

At. tllBrfOIfWELltl end of the machineI 'pro- P vide a multiple scrapplow for taking out of-the sand bed any pigs or large pieces of metal orother matter left in the bed from the previous cast. The scrapplowispreferably formed by a series .of plow blades 123 which are madefastat their upper. end to a transverse shaft 12twhich ismounted to rock inbearings-125. mounted in suitable brackets 126 .underhung from theforward end of the frame 1 ,at each side. At an intermediate point theseveral plowhlades are provided in front with aligning eyes 127 throughwhich a transverse shaft or. rod 128 is passed, and this rod, atsuitable intervals, is connected by links 129 to rocker arms.

130 which are pivotally mounted intermediate their ends by keying them.on the rocker cross shaft 131 and at their inner ends which overhangwithin the frame they carry counter-weights 132 which counter-balancethe scrap plows. The shaft 131 has connected thereto a crank 133connected by an operating rod 13 l with one of the control levers 71 .onthe operators platform. .By this arrangement the plows can be swung upand held out ofoperating position when desired.

At some suitable point on. the machine frame I mount a water tank135wvliich is' connected by suitable piping to the sprays 13.6, 137, 138and" 139 which. are arranged successively in the rear of thescrap plow123, the screen 92, the pig plows 61, and at the rear endv of themachine, and these several sprays are independently controllable byvalve means, not shown, for the purpose of bringing the sand in1.be.d.to the desired degree of moisture for. proper treatment .bythe moldroller,..and after mold roller has formed molds.

The form .of patterns on the mold. roller for the cross runnerand pigmolds .may be varied to suit the form ofpigs, and runners desired,provided that mold patterns. are I of such shape as willv draw out,without lifting sand from the bed. The accompanying drawings showfoursets of pig mold patterns 54, which abut their respective cross runnerpattern 140. Each pattern 140.

for across runner ismountezd inan indented seat or guide 141 formed inea-ch mold roller.

By this arrangement I ICC spider 142 and they are adapted to be adjustedradially in said guides in such a manner as to permit of the patternsadjustment to give a deeper or shallower cross runner relatively to thepig molds. This construction also permits adjustment of cross runner sothat either end will mold a deeper or shallower runner in relation tothe pig molds connecting therewith. The patterns 141 are held in placeby bolts 143, the. bolt hole in the seat or pattern, as desired, beingradially elongated to care for this pattern adjustment.

In practice it is found necessary when running molten metal any distanceto give the main runner a. certain amount of pitch. Therefore the tracton which the machine runs will be inclined to the desired pitch. It willtherefore be seen that if the mold rollers were made cylindrical and thepig patterns 54 were of uniform size throughout their length as isdesirable, all the pig mold imprints in the bed would be on an inclinedplane parallel to the track plane. This is not desirable, and thereforethe peripheral surfaces 144 of the mold roller on which the transverserows of pig patterns 54 are mounted are not concentric with the rolleraxis, but are formed by a circumferential series of eccentric planes,one for each longitudinal row of mold patterns and the eccentricity ofthe pattern supporting planes or surfaces 144 is such that when themachine runs on an inclined track the length 1 of one mold each moldpattern imprint in the sand will be level. In other words, the outsidesurface of this roller is composed of four like pig mold planes 144,each with its cross runner pattern subtending a quarter circle of theroller and each surface is thrown out enough to bring the periphery ofeach mold pattern on the roller as it makes its imprint in the sand to alevel plane as the machine travels down an inclined track. Obviously theamount of this eccentric displacement of the mold roller surfaces 144will be governed by the pitch of the track on which the machine operatesand the number of eccentric surfaces on the mold roller circumferencewill be governed by the number of mold patterns placed circumferentiallyin a given transverse plane about the roller. This method of forming thepig molds is best illustrated in Fig. 14 where the pig mold imprints 145are shown lying level and connected to their respective cross runnerimprint 146. The cross runner imprint does not connect with the mainrunner imprint 147, as in practice the cross runners are connected byhand tool to the main runner successively as the molds are filled withmolten iron, the molds at the lowest level being filled first.

The worm gearing acting to raise and lower the frame 1 will give thecross runner and pig mold patterns the requisite pitch to cause themetal to run along the same in the desired manner. The mold roller isheld in position andprevented from rising up when forming molds by itsown weight and by the weight of the entire machine, the roller beingswung in boxes so attached to the frame that it is necessary to lift theentire weight of one end of the machine before the surface of the rollerwould be forced from the plane to which it had been adjusted by the wormgear operating mechanism described. Obviously additional weight can beadded to the frame of the machine if needed to get the desiredcompression of sand to form the molds. The dotted line, Fig. 12indicates the inclined pitch of the mold bed previous to the formationof the pig molds and the stepped horizontal benches 148 indicate thelevel surfaces produced successively by the eccentric surfaces 144 ofthe mold roller.

The travel of this machine is positive, the power being imparted to themain axle 3 by a motor drive and the axle in turn is connected to themold roller by chain and sprocket drive of such ratio that the travel ofthe periphery of the mold roller surface where pig mold patterns areattached will at all times be equal to the travel of the periphery ofthe track wheels 2 on which the machine rests. Also, the pitch line ofthe gears and rack being in the same plane as the periphery of the trackwheels and the gears and track Wheels being of equal diameter will givean equal travel to the rack gear and to the track wheels running on therails. The racks thus insure a positive drive and will act to preventthe machine from slipping or getting out of alignment across the moldbed.

Assuming that the machine is at one end of a bed preparatory to treatingit and pre paring the molds therein, its operation is substantially asfollows. The scrap plows, rotary sand elevator, mold plows and moldroller are all lowered to operating position, the sand screen bottom 95is closed, and the frame of the machine is set to the desired pitch forthe cross runners. As the several motors are started up and the machinemoves along the bed, the scrap plows will pick up and carry to the endof the bed pigs and large scrap left in sand from former cast. Thebucket wheel elevator will lift the sand from the bed and deposit it onthe shaking screens. The screens will sift the sand, removing allparticles of iron or foreign matter remaining therein which are toolarge to pass through screens and the sand will be deposited back uponthe bed. The magnet will lift out any remaining iron particleswon andnear the surface and the screened sand will be brought to a planeparallel with a track rail by the scraper plate attached to the sandbin. If additional sand is needed,the sand valve will be operated tosupply it and the sand will be distributed on the bed by the sandscraper. The sprays will act to moisten the sand and the moisten'edvgraded sand bed will then be acted upon by the main runner and pig moldplows, the main jrunner plow cutting a deep narrow trench and the pigmold plows cutting trenches which vary in'depth responsive to the actionof the cams on the mold roller which proportion the depth of each partof the trench to the depth of the mold imprint to be madetherein. Themold-roller with its patterns following the plow trenches andco-ordinating therewith will complete the molds by imparting thenecessary compression and shape to the sand to form them; Thedisplacement of sand by the mold roller, as it travels down grade alongthe track, to form the bed into benches, tends'to build up sand at thepoints where the division walls come between cross runners and the rowof pigs preceding them, thereby insuring a firm division wall and makinglighter the dut, on. the patterns usedto form the said wall In order toprevent dragging of sand by the main runner pattern roller, due to itsvarying diameters, the latter is divided in transverse parallel planesinto sections, all r of which are separate'from the mold roller andeachpapable of rotation independently of the other and of themoldroller. In this way each separate section of the-main runner patternroller 62 Will travel with approximately the same peripheral. speed .ofmold roller surface notwithstanding their different diameters. v t

It is desirable to leave, the gears, 25 loose on the shaftBand to useclutches 149 splined on the shaft to. enable the moldroller to bedisconnected from its drive, shaft as. the machine is run back over thebed, these clutches being preferably provided with operatingconnections, not shown, to the operators platform. This will preventdriving the cams operating the plow lifting cranks when the plows arenot in service.

It is tov be understood that the mold roller can. be fabricated anydesired manner or cast integrally or in sections, andthat the machinecan be driven by electrical or othe power. V The scrap plows areflattened out at their forward ends sothat they will receive and supportthe larger pieces of iron and other matter which they are, intended tocollect from the bed asthe machine advances.

Though I have described with great pare ticularity the details oftheembodiment of the invention herein shown, it is not to be construed thatI am limited thereto, as changes in arrangement andsubstitution ofequivalents may be made by those skilled in the'art without departingfrom theinvention as'defin'ed the appended-claims I Having thusdescribed my invention, what I claim as new and desire to secure byLetters Patent, is

1. In a pig bed molding machine, a wheeled frame movable on tracks, amold roller journaled in said frame, and means to adjust the height ofthe frame relative to the tracks to control the inclination of theroller.

2. In a pig bed molding machine, a wheeled frame movable on tracks, amold roller-mounted in vertically adjustable journals in the frame, andmeans to adjust a side of the frame relative to its tracks to controlthe inclination of the roller.

3. In a pig bed molding machine, a traveling frame, a mold rollerjournaled therein and having patterns to produce the pigmold imprints inthe sand bed, vertically reciprocable plow means in advance of the moldroller, and a common co-ordinated drive for plows and roller adapted tomove the plows to vary the depth of their furrows proportionately withthe height of the following mold patterns to obtain substantiallyuniform compression of the mold bed;

4. In a pig bed molding machine, the combination with a traveling framehaving a mold roller ournaled therein, and track supports for the frame,of plow means disposed in advance of the roller and at such an angle asto pick up and remove larger pieces of metal from the sand.

5. In a pig bed molding machine,the combination with a traveling framehaving a mold roller journaled therein, and tracks for the machine, ofmeans to pick up and screen the upper layer of sand in the bed inadvance of said mold roller.

6. In a pig bed molding machine, the combination with a traveling framehaving a mold roller j ournaled therein, and tracks for the machine, ofmeans to screen from the upper layer of sand in the bed large particlesof metal and foreign matter.

7, In a pigbed molding machine, the combination with a traveling: framehaving a mold roller journale'd therein, and tracks for the machine, ofmagnetic means to remove from the surface of the bed to be molded smallmetallic particles remaining therein.

8. In a pigbed molding machine-the com bination with a traveling framehavinga mold roller journaled therein, and tracks for the machine, ofplow means to collectand. carry oft the largest pieces of foreign matterin the sand,'and means to screen out of the sand other pieces of metaland foreign matter remaining therein.

.9. In a pig bed molding machine,1the combination with a traveling framehaving a mold."roller journaled therein, and tracks for the machine, ofmeansvto screen the u'pper layer of the sand bed for the removal oflarger pieces of metaland foreign matter,

and m gnetic mea s to remove from th J screened san'd finer metallicparticles remaining therein.

10. In a pig bed molding machine, the combination with a traveling framehaving a mold roller journaled therein, and tracks for the machine, ofplow means acting to collect and carry off the largest pieces of metalremaining in the bed, means to screen the upper laver of the sand forthe further removal therefrom of pieces of metal and foreign matter, andmagnetic means to remove from the screened sand fine metallic particlesremaining therein.

11. In a pig bed molding machine, the combination with a traveling framehaving a mold roller journaled therein, of a transverse series of scrapplows mounted at the forward end of the machine and shaped and inclinedat such an angle as both to plow up the bed and to pick up and carry offlarge metal pieces remaining in the bed, and means to raise said scrapplows out of operating position.

12. In a pig bed molding machine, the combination with a traveling framehaving a mold rol er journaled therein, of a screening mechanismdisposed transversely across the machine, a transversely disposed bucketwheel, means to pick up the top layer of sand and deliver it to saidscreen mechanism for treatment in advance of said roller, and adjustablehearings to set said bucket wheel to pick up the sand above apredeterminet grade level.

13. in a pig bed molding machine, the

combination with a traveling frame having a mold roller journaledtherein, of means to prepare the sand bed for molding in advance of theroller, a scraper tograde the bed, and means carried by the machine fordelivering a replacement supply of sand to the pig bed in advance of thescraper.

14. In a pig bed molding machine, the combination with traveling framehaving a mold roller journaled therein, of means to primarily plow upand grade the mold bed to prepare it in advance of the roller, a sandlain extending transversely across the machine, and means to feed areplacement supply of sand therefrom to the bed.

15. In a pig bed molding machine, the

combination with a traveling frame having a mold roller journal-edtherein, of means to primarily plow up and grade the mold bed to prepareit in advance of the roller, a sand bin extending transversely acrossthe machine, and means to feed a replacement supply of sand therefrom tothe prepared bee immediately in advance of the scraper. 16. In a pig bedmolding machine, the combination with a traveling frame having a mold roler journaled therein, of means to remove the larger pieces of metal andforeign matter from the sand bed, scrap-er means to grade the bed, andplows to open furrows in advance of raised patterns on the mold roller.I

17. In a pig bed molding machine, the combination with a traveling framehaving a mold roller journaled therein, of plow means disposed to openfurrows in advance of the raised patterns on mold rollers, and means tovary the depth of the plow furrows proportionately to the depth of themold imprints to be made therein.

18. In apig bed molding machine, a traveling frame, a mold rollerjournaled therein and having pig, cross runner and main runner patternsthereon, a fixed plow to open the bed in advance of the main runnerpattern, intermittently reciprocable plows disposed in alignment withand in advance of the pig patterns, and operating means to reciprocatesaid latter plows in co-ordination with the mold roller to vary thedepth of the pig mold furrows cut by them.

19. In a pig bed molding machine, a traveling frame, a mold rollerjournaled therein and having patterns for producing the pig moldimprints in the sand bed, plows to open furrows in. line with each pigmold pattern, a cam on the mold roller, and mechanism operated by thecam to raise and lower said plows to vary the depth of their furrows insubstantial proportion to the height of the pattern where it enters thefurrow.

20. A pig bed molding machine comprising a frame having wheels andtracks therefor, a. mold roller journaled in the frame, a rack andpinion drive to advance the frame on said tracks, the pitchcircumference of the pinions and the tread circumference of the wheelsbeing equal, and a drive for the pinions and mold roller adapted to giveboth the same peripheral velocity.

21. A pig bed molding machine in accordance with claim 20, in which themold roller has raised patterns rising in a plane parallel with thedirection of movement of the frame and having the ends of the raisedpatterns tapered to enter and leave the sand bed without breaking same,notwithstanding their greater peripheral velocity than that of the moldroller.

22. A pig bed molding machine comprising a vertically adjustable moldroller, wheel supports for the machine, tracks for said wheels, racksalongside the tracks, pinions engaging the racks, adriving motor in themachine, driving connections from the motor to the mold roller and tothe pinions adapted to give both the same peripheral speeds, a highspeed reverse drive for the pinions, and clutch means controlling thedrives to the pinions.

23. A pig bed molding machine comprising a vertically adjustable moldroller, wheel supports for the machine, tracks for said wheels, racksalongside the tracks, pinions engaging the racks, a driving motor in themachine, driving connections from the motor to the mold r'oller and tothe pinions adapted to give both the same peripheral speeds, a highspeed reverse drive for the pinions, and clutch means controlling thedrives to the pinions and roller.

24. In a pig bed molding machine, a mold roller having at one end a mainrunner mold Wheel mounted to rotate independently of the mold roller,said main runner Wheel being divided in transverse planes at rightangles to its axis into independently rotatable sections.

25. In a pig bed molding machine, a mold roller having longitudinalseriesof spaced pig mold patterns, and a longitudinal cross runnerpattern associated with each longitudinal row of pig patterns andmounted for'radial adjustment in the roller.

26;- In a pig bed molding machine, a mold roller journa-led therein andprovided With longitudinal series of peripheral pig mold patterns, across runner pattern associated With each longitudinal row of pig moldpatterns, and independent means to adjust said runner pattern bot-hradially and angularly relatively to the axis of the roller.

27. In a pigbed molding machine, a frame having a mold roller journaledtherein, wheels for supporting the frame, axles on Which said Wheels aremounted, and journal boxes for the axles vertically a-djustablyconnected to the frame.

28. In a pig bed molding machine, a frame having a mold roller journaledtherein, Wheels for supporting the frame, axles on Which said heels aremounted, and journal boxes for the axles vertically adjustably connectedto the frame by means of pairs of links Whichstraddle the frame and 30.In a pig bed molding machine in ac cordance, with claim 29, in which thescreen comprises reversely reciprocable upper and oWer screens with thelower screen provided With a sectional drop bottom, and means to holdthe bottom in closed position during the operation of the screen.

31. In a pig bed molding machine, the combination With a traveling framehaving a mold roller jo-urnaled therein, of means independentlyadjustable to agitate and grade the sand bed'in advance of the roller,means to supply replacement sand to maintain the desired grade level ofthe bed, and means to moisten the sand;

In testimony whereof I a'flix my signature.

SAMUEL STEWART.

